A radio frequency identification (RFID) tag is an object that can be attached to or incorporated into a product, animal, or person for the purpose of identification using radio waves. RFID tags may be very small. In one embodiment, an RFID tag is 0.4 mm squared, contains a 128-bit read only memory (ROM) capacity, has a read range of up to 30 cm, and employs no battery. Continuing advances in technology can be expected both to reduce RFID tag size further and to increase RFID tag memory capacity. RFID tags can be printed on objects, inserted into objects, woven into objects, adhered to objects, and incorporated into or attached to objects in other ways. RFID tags typically contain at least two parts. The first part is an integrated circuit for storing and processing information, modulating and demodulating a radio frequency (RF) signal and perhaps other specialized functions. The second part is an antenna for receiving and transmitting the RF signal.
Two-dimensional bar codes are designed to be reliably read from various reading angles and orientations by a low-quality scanner or a camera. Two-dimensional bar codes may include SEMACODE, SHOTCODE, and other two-dimensional bar codes.